Boom lifting device



Dec. 4, 1956 J. c. HUSSONG ET AL 2,772,789

BOOM LIFTING DEVICE Filed OCT, 28, 1954 4 Sheets-$heet l H lN VENTOR JAMES C. HUSSONG 8} KIRWAN Y. MESSICK ATTORNEY 1956 J. c. HUSSONG ET AL 2,772,789

BOOM LIFTING DEVICE filed on. 28, 1954 4 Sheets-Sheet .2

INVENTOR JAMES C. HUSSONG KIRWAN Y. MESSICK ATTORNEY Dec. 4, 1956 J. c. HUSSONG ET AL 2,772,789

BOOM LIFTING DEVICE Filed Oct. 28, 1954 4 Sheets-Sheet 5 INVENTOR JAMES C. HUSSONG KIRWAN Y. MESSICK TORNEY Dec. 4, 1956 J.. c. HUSSQNG ET AL 2,772,789

BOOM LIFTING DEVICE 4 Sheets-Sheet 4 Filed Oct. 28,- 1954 INVENTOR JAMES C. HUSSONG Kl RWAN Y. MESSlCK BOOM LIFTING DEVICE James C. Hussong, Pikesville, Md., and Kirwan Y. Messick, Arlington, Va., assignors to Thompson Trailer Corporation, Pikesville, Md., a corporation of Virginia Application October 28, 1954, Serial No. 465,312

4 Claims. (Cl. 212-8) This invention relates to a device for lifting a load. More particularly our invention is concerned with a lifting device adapted to be operated from a platform or supporting structure such as a truck. In another aspect our invention relates to a truck which includes as an integral part our novel lifting structure.

It is commonplace in many industries to handle various articles, heavy equipment, and other loads by means of certain mechanical devices or arrangements. One class of these devices includes as a principal lifting element a member or boom extending from a base or frame structure. It is frequently desirable to afford maximum maneuverability to the boom without of course giving rise to bulky, expensive structures occupying uneconomical and inconveniently large areas of operation. Thus the operators may wish to maneuver a load with the boom extending in one direction from its supporting structure and then place the boom in an inoperable or stored position particularly useful in transporting the device from one location of use to another.

In one aspect, our invention relates to a boom lifting device adapted to be operated from a supporting structure or operating base designed to move from one location to another, for instance a truck. The truck is maneuvered to a desired position and the boom is extended from its end to an operative position for lifting a load. However, in many instances, the device must be transported considerable distances or maneuvered in confined spaces which require that the boom be stored in a position extending over the truck. Our invention has significant utility in lifting devices of this type.

It is extremely important in these boom lifting devices that the boom be easily moved from an operating to a stored position. In most fields of application the operator must store the boom at least once if not many times a day and structures requiring complicated, tedious and timeconsuming operations to accomplish this maneuver are of course disadvantageous.

When an operator mounts a lifting device on the end of a truck he naturally desires to have the truck open or unoccupied in order that it can be used in the normal manner for carrying articles or for transporting men whether the boom be in operative or stored position. It is further desirable that the lifting device should not protrude to any consderable extent beyond the end of the truck to reduce maneuverability of the truck or subject the device to hazards of collision. Yet the lifting apparatus must be placed near the end of the truck to afford maximum utility. Concisely, the operator desires to incorporate on the truck a lifting device which detracts a minimum from the maneuverability of the truck and its usefulness as a carrier, yet at the same time the boom must be able to handle heavy loads easily.

The boom lifting device of our present invention meets all of the above noted and many other criteria which distinguish a commercially acceptable structure. The lifting booms of the structure of the present invention can be moved from operative to stored positions with no manual nited States Patent operation, yet mechanically the device is simple and convenient to operate. Our device can be so adapted to a truck as to leave it practically entirely free for its normal carrying functions. Moreover, no part of our lifting structure need be extended beyond the truck when in stored position so dangers of collision are not increased and loss of maneuverability is not encountered. Our structure has good adaptability, that is, it can be placed on existing trucks as a separate or an integral unit, or, alternatively, it can be built as an integral part of a new truck.

All of the above and many other advantages features of our apparatus will be apparent from the detailed description which follows with reference to the accompanying drawings, in which:

Figure l is a perspective view of our lifting device in operative position and mounted on a truck as a supporting base;

Figure 2 is a side view of the apparatus of our invention shown with its booms in several positions and with the apparatus mounted on a truck as a supporting base;

Figure 3 is a side view of our device in stored position when mounted on a truck and the near sideboard of the truck has been removed for purposes of illustration;

Figure 4 is a side view of an alternative embodiment of the apparatus of our invention mounted on a truck as a supporting base; and

Figure 5 is a diagrammatic sketch of a fluid system suitable for use in operating our boom lifting device.

Referring particularly to Figure 1, our device comprises two spaced apart supporting base members 10 and 11 having rigidly attached at their respective rear ends vertical supporting members 12 and 13. The base members are mounted at separate sides of truck 41. Passing between the respective bases and the vertical supporting members are inclined supporting bars 14 and 15 rigidly attached to the front of their respective base members and to the upper portion of their respective vertical support members. At an upper portion of the vertical support members booms 18 and 19 are pivotally mounted on lugs 16 and 17. These booms extend toward each other as they extend radially between the vertical support members and are joined at their radial extremities by pulley 21.

The booms, preferably box booms as shown, are reinforced by bar 22 passing between the booms. The supporting bar 22 is mounted between the booms at a point along their lengths so that when cable 32 is strung only over pulley sheave 22a on bar 22 and is supporting a load, the load is well behind the truck when the booms are horizontally extended to the rear. The upper edges of the booths (the term upper refers for convenience to the booms in the position of Figure l) are straight between their pivot points and radial extremities. The opposite or lower edges of the booms decline from their pivot points to give a maximum cross-section at a point known as the fish belly and then incline toward the radial extremities of the booms. The maximum cross-sections of the booms are preferably located at the point of maximum stress when the booms are supporting an extraneous load.

Pivotally mounted on supporting base 10 at 25 (Figure 3) on member 26 is the lower end of single acting hydraulic lift ram 27. The upper end of ram 27 is pivotally mounted to lug 23 located on the upper edge of boom 18 in the approximate plane of the cross-section of the fish belly of the boom. The ram passes to the inside of boom 18 as the ram extends to lug 23. Although ram 27 can be pivoted to another point on boom 18 such as at its fish belly, we have found it highly advantageous to connect the ram as shown in order to give stability to the booms when handling loads particularly when near a vertical position.

The lower end of single acting hydraulic lift ram 28 is pivotally connected at 25a to member 26a which is rigidly mounted on supporting base 11. Pivot point 25a is in the approximate vertical plane of the pivot points of booms 18 and 19 at lugs 16 and 17. The upper end of ram 28 is pivotally connected to lug 24 located at the fish belly of boom 19. Cable 32 passes from winch 29 over pulley sheave 22a through pulley 21 over its sheave 31. Lifting hook 33 is attached to the free end of the cable.

In operation of our device when in the position of Figure 1, the load to be lifted can be attached to hook 33 and then lifted by raising booms 18 and 19 by passing hydraulic fluid into lifting rams 27 and 28 by way of lines 34 and 35. As the fluid passes into the hydraulic rams, pistons 36 and 37 move upwardly, thus moving the booms upwardly and lifting the load. Alternatively, the load can be attached to hook 33 and then lifted solely by taking up cable 32 on winch 29. To lower the load, the fluid is released from the lifting rams 27 and 28 by way of lines 34 and 35 or the winch cable is unwound. Pumping of the fluid into the rams and release of the fluid are controlled by a suitable fluid system such as that described below.

In Figure 2 our lifting device is also shown mounted on truck 41. Truck 41 has at each side of its end a jack 44 attached to give greater stability in lifting a load. Jack 44 is shown at the rear of the near side of the truck and a similar jack (not shown) is placed at the rear of the far side of the truck. In Figure 2 the boom is shown in solid lines in one operative position extending to the rear of the truck and at an angle to the horizontal of about 30. Also in Figure 2 the booms are indicated by phantom lines in a near parallel position extending from the rear of the truck and in other positions occupied while moving between an operative and the stored position. The booms .can be lowered from the solid line position in Figure 2 to the approximately horizontal position to the rear merely by releasing fluid from the hydraulic lifting rams. Our apparatus has particular utility since it may be lowered to this horizontal position in order to give the truck additional maneuverability. When the boom is in this position the truck can go forward or backward as when passing beneath electrical wires or other low structures and is hampered in this respect only by the height of the truck itself. Also at this lowered position a man can more easily reach the pulley 21 and place the winch line or another line around the pulley sheave.

In Figure 4 which is similar to Figure 2 we have illustrated hydraulic ram 28 pivoted to the rear of the approximate vertical plane of the boom pivot points which is a possible but less preferred location for the ram attached to boom 19. When ram 28 is in the position shown in Figure 4 better leverage might be obtained for moving the boom to position 43 but this exposes the ram to greater hazards in truck collisions and can reduce the trucks maneuverability.

A third position of the booms indicated by phantom lines 43 in Figure 2 illustrates the booms just to the rear of the vertical plane of their pivot points. The booms are carried to this position from the solid line position shown in Figure 2 at the rear of the truck by pumping fluid to both hydraulic rams until ram 27 reaches its maximum extension and then pumping fluid to ram 28 until it reaches its maximum extension while releasing fluid from ram 27. To move the boom from position 43 to any position extending further over the truck as to the completely stored position (Figure 3), the essential operation performed by the operator is merely the release of the fluid from both hydraulic lifting rams slowly to let the booms descend under their own weight.

The hydraulic system for operating our device can be located where desired, for instance, at the rear of truck 41. The system has a hydraulic pump 60 for pumping the pressuring fluid to the rams 27 and 28. The pump is driven by a power take-off mechanism which is connected to the power source such as at the transmission of the truck drive. The pump takes fluid from a reservoir 61 and passes it through a flow line 62 to a control mechanism 63. Separate flow lines 34 and 35 lead from the control mechanism to each of the rams for transporting fluid between the control mechanism and the respective rams. Another flow line 66 leads from the control mechanism to the system reservoir. The control mechanism provides for independent control of the hydraulic rams so that fluid may be passed to or released from each ram either at the same time or independently. A suitable mechanism is a Hydreco V12 Series valve having two plungers, one for each of our cylinders, which are actuated by separate levers.

Considering the booms to be in the stored position, the pump is started and both control levers in a two lever system are in a neutral position which by-passes fluid back to the reservoir. The levers are then moved to a first position and fluid passes to both rams. When the booms are in position 43 they are stalled since ram 27 is then pushing against ram 28, which is fully extended. The control lever of ram 28 is then moved to a second position which permits release of fluid from ram 28 until the booms reach position 45 whereupon they stall since the extension of ram 27 is at the maximum. To lower the booms to the rear of the truck the lever of ram 27 is then put to the position for releasing fluid from the ram. The booms then descend since both control levers are in the fluid releasing position.

To store the booms from this position, the levers are placed in the first position until the booms reach position 45 where they stall due to the maximum extension of ram 27 Then the lever of ram 27 is moved to the position at which fluid is released from ram 27 until the booms stall at position 43 due to the maximum extension of ram 28. The lever of ram 28 is moved to the fluid releasing position to lower the booms to the stored position while passing through the position indicated by phantom lines 44.

It is seen that the operator of the lifting device has a large degree of control over the booms and can move them from an approximately horizontal position extending to the rear of the truck to an approximately horizontal position extending over the truck. Thus, the boom can be stored without any manual effort. This action is in marked contrast to boom lifting devices which necessitate the removal of a pin from the boom to put it in stored position. The removal of such pins is diflicult and time-consuming since they frequently become bound by side stresses. Further, constant hammering of the pins can distort them to unusable shapes and may even peen or distort them so that they cannot be removed by hammering.

In order for our booms to be operative as described, the lower end of one ram must be pivoted at a point whose vertical plane is sufficiently to the front of the vertical plane of the boom pivot points to carry the center of gravity of the booms to the rear as they pass over their vertical position. At the same time, the lower end of the other ram must be pivoted at a point whose vertical plane is no farther to the front of the device than the approximate vertical plane of the boom pivot points. Stated another way, this lower pivot point of the ram is beneath or to the rear of the approximate vertical plane of the boom pivot points. In describing our device the terms front and rear are used for convenience; however, they are of course merely relative expressions.

Whether the lower end of ram 28 be pivoted directly beneath its boom pivot point or rearwardly thereof can depend on the connection of the upper end of the ram to its boom 19. The controlling factor is that the center of gravity of the booms must be to the front of their pivot points when ram 28 is fully extended. As illustrated in the drawings, the lower end of ram 28 is pivoted directly beneath its pivot point since due to the connection of the ram to the fish belly of boom 19, the center of gravity of the booms is to the rear of their pivot points when ram 28 is fully extended. Positive control of the booms is maintained as they pass over their vertical point when moving in either direction so that the booms never have a chance to drop either to the front or the rear which could result in complete loss of control of the booms. Preferably, the lower ends of rams 27 and 28 are located so that the rams are extended to the maximum when the booms radial extremities make at least about a 5 angle with the boom pivot points. Naturally, this angle will be to the front or to the rear of the boom pivot points depending on the ram which is fully extended. Thus, the booms can be moved over their complete path of travel with no manual effort and positive control is provided as the booms pass in either direction over their vertical position.

In Figure 1 it is evident that when our device is incorporated on a truck the normal carrying functions of the truck are not hampered. Since the booms are pivoted at the rear upper portion of the sideboards 50 and 54, the entire middle of the truck frontwards to the winch 29 is open whether the booms be in operative position as in Figure 1 or in the stored position as in Figure 3. The truck can then be utilized fully for carrying tools and men or any other materials desired and the men have easy access to the truck. Actually, the only parts of our device which can be said to occupy any part of the normal carrying space are the hydraulic lifting rams 27 and 28 and, depending upon the particular structure, possibly supporting members 10, 11, 12, 13, 14 and 15. It will be appreciated of course that these members are placed at the sides of the truck and thus do not occupy a substantial portion of its area. Alternatively, these supporting members can be built as an integral part of the truck sideboards 50 and 54 and in this instance only the hydraulic rams would occupy any area of the truck. A cover 51 can extend over the front area of the truck for protective purposes.

Although pulley sheave 22a is located on bar 22 as a guide means when cable 32 is passed through pulley 21, the sheave 22a has a more important function. It will be appreciated that when a load is connected to hook 33 the booms can be moved toward the stored position and thus deposit the load on the truck. However, when desiring to place a load on the truck the load is better controlled if the cable 32 be strung only over sheave 22:: so that hook 33 can be connected to the load directly beneath this sheath. The load is then lifted and placed in the open portion of the truck by moving the booms over the truck.

From this description it is seen that we have invented a highly efficient and useful lifting device incorporating the many features operators have long desired. Yet our device is not complicated mechanically, is easy to operate, and is economical both in orginal cost and in upkeep.

Having described our invention, we claim:

1. In a lifting device comprising first and second spaced apart supporting means, a first boom pivotally mounted at an upper portion of said first supporting means, a second boom pivotally mounted at an upper portion of said second supporting means, said booms being joined radially outward from their pivot points, first and second single acting hydraulic lift means respectively pivotally mounted in association with lower portions of said first and second supporting means and with said first and second booms, said first hydraulic lift means being mounted on its supporting means at a point to a first side of the vertical plane of the boom pivot points so that when the first hydraulic lift means is fully extended the booms center of gravity is to a second side of the vertical plane of the boom pivot points, said second hydraulic lift means being mounted on its supporting means so that when the second lift means is fully extended the center of gravity of the booms is to the first side of the vertical plane of the boom pivot points, said first and second hydraulic lift means being elfective to move the booms back and forth between an approximately horizontal position on the first side of the boom pivot points to an approximately horizontal position on the second side of the boom pivot points.

2. The lifting device of claim 1 in which said first and second supporting means are mounted on a truck.

3. In a lifting device comprising first and second spaced apart supporting means, a first boom pivotally mounted at an upper portion of said first supporting means, a second boom pivotally mounted at an upper portion of said second supporting means, said booms being joined radially outward from their pivot points, first and second single acting hydraulic lift means respectively pivotally mounted in association with lower portions of said first and second supporting means and with said first and second booms, said first hydraulic lift means being mounted on its supporting means at a point to a first side of the vertical plane of the boom pivot points so that when the first hydraulic lift means is fully extended the booms center of gravity is to a second side of the vertical plane of the boom pivot points, said second hydraulic lift means being mounted on its supporting means in the approximate vertical plane of the boom pivot points and mounted on its boom so that when the second lift means is fully extended the center of gravity of the booms is to the first side of the vertical plane of the boom pivot points, said first and second hydraulic lift means being effective to move the booms back and forth between an approximately horizontal position on the first side of the boom pivot points to an approximately horizontal position on the second side of the boom pivot points.

4. In a lifting device comprising first and second spaced apart supporting means, a first boom pivotally mounted at an upper portion of said first supporting means, a second boom pivotally mounted at an upper portion of said second supporting means, said booms being joined radially outward from their pivot points, first and second single acting hydraulic lift means respectively pivotally mounted in association with lower portions of said first and second supporting means and with said first and second booms, said first hydraulic lift means being mounted on its supporting means at a point to a first side of the vertical plane of the boom pivot points so that when the first hydraulic lift means is fully extended the booms center of gravity is to a second side of the vertical plane of the boom pivot points, said second hydraulic lift means being mounted on its supporting means in the approximate vertical plane of the boom pivot points, said second hydraulic lift means being mounted on the second boom along its edge which is lowermost when the boom is on said second side of the boom pivot points so that when the second lift means is fully extended the center of gravity of the booms is to the first side of the vertical plane of the boom pivot points, said first and second hydraulic lift means being effective to move the booms back and forth between an approximately horizontal position on the first side of the boom pivot points to an approximately horizontal position on the second side of the boom pivot points.

References Cited in the file of this patent UNITED STATES PATENTS 2,336,965 Shoemaker Dec. 14, 1943 2,598,517 Drott May 27, 1952 2,687,809 Balogh Aug. 31, 1954 2,689,053 Olson Sept. 14, 1954 

